When core.sharedRepository is used, set_shared_perm() in path.c
needs lstat() to return the correct POSIX permissions.
The default for cygwin is core.ignoreCygwinFSTricks = false, which
means that the fast implementation in do_stat() is used instead of
lstat().
lstat() under cygwin uses the Windows security model to implement
POSIX-like permissions. The user, group or everyone bits can be set
individually.
do_stat() simplifes the file permission bits, and may return a wrong
value. The read-only attribute of a file is used to calculate the
permissions, resulting in either rw-r--r-- or r--r--r--
One effect of the simplified do_stat() is that t1301 fails.
Add a function cygwin_get_st_mode_bits() which returns the POSIX
permissions. When not compiling for cygwin, true_mode_bits() in
path.c is used.
Side note:
t1301 passes under cygwin 1.5.
The "user write" bit is synchronized with the "read only" attribute
of a file:
$ chmod 444 x
$ attrib x
A R C:\temp\pt\x
cygwin 1.7 would show
A C:\temp\pt\x
Signed-off-by: Torsten Bögershausen <tboegi@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
lstat/stat functions in Cygwin are very slow, because they try to emulate
some *nix things that Git does not actually need. This patch adds Win32
specific implementation of these functions for Cygwin.
This implementation handles most situation directly but in some rare cases
it falls back on the implementation provided for Cygwin. This is necessary
for two reasons:
- Cygwin has its own file hierarchy, so absolute paths used in Cygwin is
not suitable to be used Win32 API. cygwin_conv_to_win32_path can not be
used because it automatically dereference Cygwin symbol links, also it
causes extra syscall. Fortunately Git rarely use absolute paths, so we
always use Cygwin implementation for absolute paths.
- Support of symbol links. Cygwin stores symbol links as ordinary using
one of two possible formats. Therefore, the fast implementation falls
back to Cygwin functions if it detects potential use of symbol links.
The speed of this implementation should be the same as mingw_lstat for
common cases, but it is considerable slower when the specified file name
does not exist.
Despite all efforts to make the fast implementation as robust as possible,
it may not work well for some very rare situations. I am aware only one
situation: use Cygwin mount to bind unrelated paths inside repository
together. Therefore, the core.ignoreCygwinFSTricks configuration option is
provided, which controls whether native or Cygwin version of stat is used.
Signed-off-by: Dmitry Potapov <dpotapov@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
